1. Technical Field
The present disclosure relates to a light-emitting device.
2. Description of the Related Art
The light-emitting diodes (LEDs) of the solid-state lighting elements have the characteristics of the low power consumption, low heat generation, long operational life, shockproof, small volume, quick response and good opto-electrical property like light emission with a stable wavelength, so the LEDs have been widely used in household appliances, indicator light of instruments, and opto-electrical products, etc. As the opto-electrical technology develops, the solid-state lighting elements have great progress in the light efficiency, operation life and the brightness, and LEDs are expected to become the main stream of the lighting devices in the near future.
Generally speaking, the conventional LED is driven by direct current (DC). An AC-DC inverter is required to invert DC to AC. Since the inverter has a large volume and heavy weight, the cost is added and the power is loss during inverting. It is difficult for LED to compete with the existing light source mainly because of the price concern. Therefore, there is a need for development of an AC-operated LED device without the AC/DC inverter.